Boxwood plants have been grown for centuries to provide attractive ornamentation, and commonly are associated with plantings indicative of distinction and nobility. Among these is Buxus sempervirens or Common Boxwood which often has been grown in North American gardens from colonial times forward.
The new Boxwood plant of the present invention was discovered in 1964 while growing as a chance seedling in a garden cultivated and tended by man at Charlottesville, Va., U.S.A. Buxus sempervirens or Common Boxwood plants were prominently being grown in the garden where the new plant was discovered. While the exact parentage of the found plant is unknown, the plant is a new cultivar of Buxus sempervirens. The plant of the present invention was selected and has been carefully preserved in view of its distinctive combination of characteristics. Upon transplanting to South Carolina, the unique combination of plant characteristics has been carefully observed and has been confirmed. Had the plant not been discovered and preserved, it would have been lost to mankind.
It was found that the new Boxwood plant of the present invention displays the following combination of characteristics:                (a) displays a pronounced upright growth habit,        (b) displays throughout the year attractive deep green leaves having a glossy upper surface in the substantial absence of winter bronzing,        (c) forms branches of superior strength that commonly will resist snow and ice damage during winter months,        (d) displays good resistance to disease and insects, and        (e) is particularly well suited for providing distinctive ornamentation in the landscape.        
The new cultivar well meets the needs of the horticultural industry as a quality woody ornamental. The upright growth habit combined with other characteristics renders the plant well capable of being grown as an ornamental specimen or accent plant at the end of a walkway or as a foundation plant at the corners of a residence or other building. Additionally, it can be grown to advantage as a tall hedge or in containers or pots in a patio setting, etc. The foliage also can serve as a holiday decoration.
The plant performs well while utilizing conventional cultural practices for the growth of Boxwood. Good winter hardiness has been observed. The plant performs best in well drained soil. The plant additionally has not been subject to damage by deer.
The ability of the new plant to well withstand common Boxwood pests and diseases during observations to date has been noteworthy and thereby is capable of providing a significant benefit to Boxwood growers.
The new plant can be readily distinguished from Common Boxwood, as well as all other upright commercially available Boxwood cultivars. More specifically, Common Boxwood commonly displays a dissimilar somewhat spherical non-upright growth habit. Significant differences also are apparent when compared to the upright ‘Dee Runk’ and ‘Green Mountain’ Boxwood cultivars (both non-patented in the United States). The ‘Dee Runk’ cultivar is a considerably more rapid grower and displays considerably less sturdy branches than the new cultivar. The ‘Green Mountain’ cultivar displays an upright habit that commonly is broader at the base, is less uniform, and is more informal in overall appearance. Also, the branches of ‘Green Mountain’ are less rigid, and the leaves of ‘Green Mountain’ are less glossy and commonly are lighter green in coloration particularly during the winter.
Asexual reproduction of the new cultivar has been carried out at Greenville, S.C., U.S.A., and Piney River, Va., U.S.A. Such propagation has included the use of stem cuttings and layering. Stem cuttings can be taken after new growth has hardened in late summer into winter and thereafter caused to root with the aid of a growth hormone in accordance with conventional techniques. The asexual propagation has confirmed that the unique combination of characteristics of the new cultivar is stably established and is well transmitted to successive generations. The new cultivar asexually reproduces in a true-to-type manner.
The new plant has been named ‘Thomas Jefferson’ in view of our third President's association with Charlottesville, Va., U.S.A., where the new plant was discovered.